plastic hydraulic tubing
Posted: Sat Feb 18, 2012 9:49 am
After seeing Angus's blown hydraulic lines and the recent thread, I have
been going through the archives and looking up some specs. I don't
remember seeing any identifying marks on Angus's tubing which makes me
wonder what it is. I did not notice any scratches or nicks in the
vicinity of the blowouts which would have weakened it. Manufacturers of
plastic tubing seem to recommend a 4 or 5 factor of safety which means
that the burst rating should be 4 or 5 times higher than the system
pressure.
The archives have reports of different types of tubing coming with
different kits. Mine (kit #18) is clearly labelled Nylon 3/8 x .295 Made
in Canada. That is .040" wall thickness.
Wayne mentions Parker NR6 .048 wall thickness which would be stronger
(thicker wall) and a known quality. I found Wayne's post of
5/14/04 is interesting for its method of tightening the fittings but
that wouldn't affect mid line blowouts. It appears that one or more
folks have switched to brass fittings because of seepage at the fittings
though.
I won't be float building for awhile but my current conclusion is to
only use plastic tubing if it is clearly marked and at least .048 wall
thickness and also to check into the truck air brake line that Drew used
since I'll probably toss the .040 tubing that I have. I think at this
point I'd assume that any unmarked tubing is low pressure cheap milky
hardware store poly tube and not let it near my aircraft. I recall that
the factory Elite was plumbed with braided steel lines not plastic...
Darn, now I'm again starting to wonder about the 1/4" x .035 wall
thickness brake lines as well...
Ken
-----------------------------------------------------------------
List archives located at: https://mail.dcsol.com/login
username "rebel" password "builder"
Unsubscribe: rebel-builders-unsubscribe@dcsol.com
List administrator: mike.davis@dcsol.com
-----------------------------------------------------------------
been going through the archives and looking up some specs. I don't
remember seeing any identifying marks on Angus's tubing which makes me
wonder what it is. I did not notice any scratches or nicks in the
vicinity of the blowouts which would have weakened it. Manufacturers of
plastic tubing seem to recommend a 4 or 5 factor of safety which means
that the burst rating should be 4 or 5 times higher than the system
pressure.
The archives have reports of different types of tubing coming with
different kits. Mine (kit #18) is clearly labelled Nylon 3/8 x .295 Made
in Canada. That is .040" wall thickness.
Wayne mentions Parker NR6 .048 wall thickness which would be stronger
(thicker wall) and a known quality. I found Wayne's post of
5/14/04 is interesting for its method of tightening the fittings but
that wouldn't affect mid line blowouts. It appears that one or more
folks have switched to brass fittings because of seepage at the fittings
though.
I won't be float building for awhile but my current conclusion is to
only use plastic tubing if it is clearly marked and at least .048 wall
thickness and also to check into the truck air brake line that Drew used
since I'll probably toss the .040 tubing that I have. I think at this
point I'd assume that any unmarked tubing is low pressure cheap milky
hardware store poly tube and not let it near my aircraft. I recall that
the factory Elite was plumbed with braided steel lines not plastic...
Darn, now I'm again starting to wonder about the 1/4" x .035 wall
thickness brake lines as well...
Ken
-----------------------------------------------------------------
List archives located at: https://mail.dcsol.com/login
username "rebel" password "builder"
Unsubscribe: rebel-builders-unsubscribe@dcsol.com
List administrator: mike.davis@dcsol.com
-----------------------------------------------------------------